Why not simply remove an existing plug and see what it is from the writing on the insulator?
If purchasing online, beware of the many fakes that exist, which may look perfectly normal right down to packaging. One test for this might be the price; I have seen sets of 4 NGK plugs for £40+ but also the “same” thing for around a tenner. If unsure, best to stick to reputable dealers/suppliers.


Doug
2011 Plus 4 in Rich Maroon

1972 750 “ComDom” sprinter
1958 Triton 650
1992 Triumph Trophy 900